On the Customer Order Lines form, this field displays the total price for this line/release, calculated by multiplying the Qty Ordered by the Unit Price.
On the Consolidated Invoices Workbench form, the field displays the extended price of the invoice line item in the browser, calculated as:
Extended Price = Qty To Invoice * Unit Price (1.0 - (Sales Discount / 100))
Qty To Invoice appears in the invoice line browser. Unit Price and Sales Discount appear above the browser; values of the two fields are from the Customer Order Lines form.